Li, M (reprint author), Chinese Acad Sci, Inst Phys, POB 603, Beijing 100080, Peoples R China.
We report our recent experimental results on solid-liquid interfaces. A set-up for X-ray scattering from the liquid-solid interfaces has been successfully installed at the Diffuse Scattering Station of the Beijing Synchrotron Radiation Facility. The samples were prepared by evaporation of isopropanol solutions of 10, 12-Tricosadiynoic acid ( TCDA) deposited on clean silicon surfaces. The in situ X-ray measurements show that the multilayers transit from a crystalline state to a liquid crystalline state after contacting with water solutions for a long time. The linear elastic theory of liquid crystals can account for the thermal fluctuations of the bilayers only on large scales. The deviation from the linear elastic theory is attributed to the existence of defects in the multilayers. This hypothesis is supported by the observation that polymerization enlarges the displacement field of the defects.